The critical field curve of aluminum has been measured from
T to 0.30 K, at pressures ranging from 0 to 7200 psi. Using caloric
metrically derived values for the low-temperature superconducting
electronic specific heat, the data have been extrapolated to T 0,
yielding values for Ho and gamma These values and experimental results
for Tc are then used to calculate the superconducting electronic
entropy and the deviation of the critical field curve from parabolicity
over the entire temperature range. The results show
excellent agreement with previous calorimetric measurements of the
thermodynamic properties of superconducting aluminum. The shape of
the reduced critical field curve shows no pressure dependence over
the range of pressures used. The dependence of Ho, Tc, and gamma on
pressure are in fair agreement with previous work by Gross and Olsen.